There was a thread on this a little while ago, with some posters apparently mainly thinking in terms of "peak lopping as with pumped storage.
While fairly technical, this helps to explain how batteries may help improve stability as the grid becomes more volatile owing to renewables.
It's a bit outside my area of experties, but I work on the basis that National Grid will know what they are talking about, and Kathryn is an independent consultant, not a sales person for batteries.
TNP has pointed out the importance of the inertia of spinning turbines in traditional coal-fired power stations in stabilising the grid frequency, several times here.
As for pumped storage, at Dinorwig, our biggest pumped storage facility, a single 450-tonne generator can synchronise and achieve full load in approximately 75 seconds from standstill. With all six units synchronised and spinning-in-air (water is dispelled by compressed air and the unit draws a small amount of power to spin the shaft at full speed), 0 MW to 1800 MW load can be achieved in approximately 16 seconds.
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But the Tesla battery in Oz has a response time of 0.2 seconds, so fast in fact that Tesla claim they're not getting paid for half of the electricity that they supply, because the electricity board only monitors the supply every six seconds so misses a lot of it.
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Whether there's any real benefit in a response time of 0.2 seconds over 16 seconds, I don't know.
Peak lopping with batteries is fine; it's what the Tesla battery in Oz is used for. If CO2 is a problem, then using batteries for peak lopping is probably a better bet than banks of diesel generators or OCGT's that switch in at a moment's notice.
The trouble is, too many people think of them as being eventually able to supply base load to the grid 24/7 WTWDBATSDS for days on end. They will never be able to do that, simply because there'll never be enough of them, and re-charging them would mean roughly doubling our existing generating and transmission capacity, let alone raising the question as to where all that electricity for re-charging is going to come from?
We *used* to think of peak lopping as coping with short peaks in demand, perhaps to save bringing large plant on-line.
The difference is, as we increase renewables there is more volatility on the supply side, and as we give up on large rotating plant (which can be kept on part load and brought up quickly to provide frequency control). So frequency control becomes really important. National Grid needs to find a way of paying for that, so that investors decide it is worth building suitable plant (like batteries) and other generators want to operate their plant to capture that income.
In the old days, there were not that many things that counted as "ancilliary services". One was "black start" capability, another was supply of MegaVars. (Interestingly, Magnox nuclear plant was particularly good at that: because the reactors had to be downrated early in their lifetime, their generators ended up containing more copper than they needed for their available power output. When you are generating reactive power you have larger currents in your rotor and stator windings, hence more resistive loss, hence need more copper to avoid cooking your insulation).
It's easy really, we know it's never calm across the UK for more than a week at a time, so all we need is enough windmills to keep them charged, and a battery bank.
The windmills should fit in Wales if we fill it all the way across, and the battery bank shouldn't be much bigger than Birmingham :}
Kathryn Porter. energy consultant whose site watt-logic is.
Batteries are relevant for very short duration overloads to prevent frequency dropping out of spec which has a huge knock-on effect. Like all the other renewable energy sources dropping off the grid if it goes too low.
Yet another example of extra costs renewables impose that never get charged to renewable operators.
I suppose that when we relied on the inertia of spinning turbines in coal-fired power stations to smooth out the momentary peaks and troughs in supply, a delay of 16 seconds while Dinorwig came up to speed could be coped with. But solar panels have no such inertia, and although wind turbines may have a little, it'll be nowhere near that of a massive steam turbine, so a battery response time of 0.2 seconds would be an advantage.
Another advantage of batteries over pumped storage is that you can put batteries anywhere, within reason, but pumped storage requires appropriate topography, and we've already used the best sites.
All I can tell you is that a company has applied for planning permission on a local brown field site to put up some kind of sub station and fill the field with second hand batteries from electric cars as a storage power source for the grid. I'm sure this is going on wherever they can get a relatively inexpensive input and output to the grid. One supposes they charge them up when there is a surplus then dumps it back when there is stress. I don't know if the project went ahead or not as some people were worried about safety. My interest was moor about wondering how they deal with big currents converting from and to dc and ac. Brian
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